Pneumatic apparatus for discharging furnaces.



S. E. HITT. PNEUMATIG APPARATUS FOR DISGHARGING FURNACES.

APPLICATION FILED SEPT, 16, 1907.

Patented Mar. 23, 1909.

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SAMUEL E. HITT, OF PITTSBURG, PENNSYLVANIA.

PNEUMATIC APPARATUS FGR DISCHARGING FURNACES.

' Specification of Letters Patent.

Patented March 23, 1909.

Application filed September 16, 1907. Serial No. 393,200.

T 0 all whom it may concern:

Be it known that I, SAMUEL E. Him, a citizen of the United States,residing at Pittsburg, in the county of'Allegheny and State ofPennsylvania, have invented a new and useful Improvement in PneumaticApparatus for Dischargin Furnaces, of which the following is a speccation.

The apparatus is applicable to what are known as open hearth,reverberatory, melting or smelting furnaces, to mixers, a heatedreceptacle for mixing molten metals, and to converters, in which moltenmetal is sub jected to an oxidizing blast. 1

In the manufacture of open hearth steel my apparatus is particularlyapplicable to what is known as the continuous process, in which onlyabout one quarter of the heat is tapped off at one time. In this processa highly basic ferruginous slag is formed, which floats on the surfaceof the bath and reacts upon the bath to eliminate the carbon, silicon,phosphorus, and other impurities. This slag is formed in some quantityand is generally poured off with the heat before its use fulness isgone; so it has been proposed to divert this slag in pouring and returnit to the furnace until its reacting qualities are exhausted.

It is therefore the object of my invention to provide an apparatus fordischarging such a furnace, i. 6. with an open bath, without disturbingthe slag floating upon the surface of the molten metal.

The rolling or tilting open hearth steel furnace is very effective inpouring, but is expensive both in first cost and in maintenance and forthat reason is being largely replaced by stationary furnaces. In thesestationary furnaces considerable annoyance and delay is caused by thepresent method of tapping. The spout must be well plugged with clay orother refractory material to withstand the pressure of the metal and isnot easily removed. A delay of some minutes in tapping is frequently thecause of a material change in the composition of-the metal. When, afterconsiderable effort, the plug is removed, the metal flows freely, butthe rate of flow is not subject to regulation with any degree ofprecision and the operation is crude.

It is therefore a further object of my invention to furnish a quick andefficient method of discharging a furnace and one by which the size ofthe stream can be regulated at any time during the discharge and bywhich the discharge can be instantly stopped.

In a general way, my invention consists in the use of a siphon to drawthe molten metal up over the fore plate level and discharge it at alevellower than the surface of the molten metal or bath of the furnace, andmeans for starting the siphon.

In my invention the siphon is of refractory material, such as fire brickor burnt clay, or both, either with or without a casing, closed at thepouring end with a fusible plug or plate, is air tight and has a pipeconnection for exhausting the air.

Another part of the apparatus required is some means for exhausting thesiphon, such as a vacuum pump.

In its simplest form the apparatus would consist of a direct connectionfrom the siphon to the vacuum pump, starting the pump when the vacuum isdesired.

I consider the best construction for my apparatus is with a vacuumchamber between the siphon and. the pump, or exhauster, with valves soarranged that the vacuum can be made ready in the chamber before hand,ready for use when required. As the siphon is too heavy to be lifted byhand, some means of hoisting the same into position is also required. Ialso prefer the use of flexible pipe connections between the siphon andthe vacuum chamber, so that everything can be made ready before thesiphon is strung into place. These preferred constructions are shown inthe drawings, in which:

Figure 1 is a cross section of an open hearth furnace, with the shortleg of the siphon immersed in the bath, the lower leg extending over aladle to be filled, the piping, vacuum chamber and pump being showndiagrammatically. Fig. 2 is an enlarged section of the siphon. Fig. 3-is a detail of the closed end of the siphon. Fig. l is a section on theline AA of Fig. 2. Fig. 5 is a detail showing the suspension of thesiphon.

Designation of numerals: 1 is a furnace with side door 2, fore plate 3and bath l, the flux or slag 5 floating on the surface of the bath. 6 isthe siphon suspended from the crane 7 by the hoisting cylinder 8 and thefastenings 9, yoke 10 and chains 11. The siphon 6 is connected by thevalve 12 and piping 14 with the vacuum chamber15 which is connected bypiping 16 and valve 17 with the vacuum pump 18. Flexibility in thepiping 1 1 is effected by a length of flexible piping 19. I prefer toconstruct the siphon as shown in Fig. 2, ith a casing in halves 2021,that can be bolted or riveted together, as shoun in Fig. 4. The tr. 0halves are first lined with fire brick 22 set with clay or with clayalone or other refractory ma terial. The mouth-piece 23 is a hollowcylinder such as a length of tiling or elbow. The mouthpiece 23 inplace, the two halves 2021 with linings 22 are secured together and thesiphon made air tight throughout its entire length by the use of clay orother refractory material. As the pipe connection to the vacuum chamberis liable to get stopped up before the siphon is fully exhausted and thestream of hot metal started, I prefer to make the siphon with a riser 21 of such a height that the molten metal cannot be forced to the top byatmospheric pressure, placing the pipe connection 25 at the top where itcannot be reached by the hot metal. The siphon casing is made with adetachable section 26 to facilitate the placing of the mouth piece 23.shoun in Fig. 3, the siphon 8 is closed at the pouring end by thefusible plate 27 held in position by the ring 28, hinged at 29 andsecured by a latch 30 engaging the releasing lever 31. The fusible plate27 is cemented in v. ith fire clay or other refractory material to closethe siphon air tight. l hen built up, the siphon is thoroughly baked ina drying oven to remove all traces of moisture. The fusible plate 27 isstrong enough to withstand the atmospheric pressure on the area ofopening of the siphon, but thin enough to be fused by the molten metal.The siphon (3 is sus pended by the chains 11 from the yoke 10,permitting the valve 12 to be placed directly above the riser 2 1. Theair valve 32 is placed between the valve 12 and the riser 24 for thepurpose of admitting air to stop the discharge of the siphon. The socket33, shown in Fig. 4c, is for the introduction of a handle by 'which thesiphon is manipulated. by the operator to tilt the siphon, either forthe purpose of changing the level of the pouring end, or of raising theinner or suction end out of immersion, so that the operation of theapparatus is not entirely dependent upon the hoisting mechanism. or airvalve.

The operation of my invention is as follows: The siphon being built upand made air tight, l is hoisted to a position convenient to the door,pipe connection is made, the valve 12 closed and the valve 17 opened,the vacuum chamber is exhausted by operating the pump 18 or by othermeans, the valve 17 is closed when a good vacuum is attained in thechamber 15. The furnace side door 2 is then opened, the siphon 6 swungthrough the door, the mouth piece 23 immersed in the bath 1,

the pouring end 34 adjusted to a level lower than the surface of thebath 4, and over a ladle or other receptacle to be filled, and securedin place by the anchor chain or chains 35, the valve 12 is then opened,the small volume of air in the siphon expanding into the larger chamber15 causing practically a vacuum in the siphon. The atmospheric pressureupon the surface of the bath t then causes the molten metal to flowthrough the siphon over the fore plate 8 and down the pouring end orlower leg till strikes the plate 27 which is instantly fused, allowingthe stream of molten metal to go on and disclnnge into the ladle, thusestablishing a stream which will continue to flow as long as the siphonis immersed in the bath and the pouring end 34 is at a level lower thanthe bath 4, 'L. e. enough lower to over come friction of the stream inthe pipe. V] hen the valve 32 is opened, admit-ting air to the siphon,the discharge stops immediately.

In the application of my invention to practical furnace work variousmodifications in the arrangement and detail of the appara tus willdoubtless be found advisable, as for instance the production of thevacuum, the means employed being of no consequence provided the vacuumcan be produced in the siphon instantly at the will of the operator. I,therefore, wish to reserve the right to make such changes which can bemade without departing from the spirit and original concepti n of theinvention as herein set forth.

What I claim is:

1. In a melting or smelting furnace, a portable siphon open at thesuction end for im- DIGISlOIl in the furnace bath, closed at the pouringend with a fusible closure and means for exhausting the siphon whenimmersed in the furnace bath.

2. In a melting or smelting furnace, a portable siphon 6, closed at thepouring end with a fusible closure 27, a riser 24. at the top of thesaid siphon, means for exhausting the said siphon through the riser 24and means for admitting air to the riser 241- to stop the operation ofthe siphon, substantially as specified.

In a melting or smelting furnace, a siphon of refractory material withmetallic casing, open at the suction end for immersion in the furnacebath, closed at the pouring end with a fusible closure, a riser on thesiphon, means for producing a vacuum, operating valves, flexible pipeconnection from the said vacuum producing means to the said riser andmeans for moving the siphon into the pouring position, substantially asspecified.

l. in a melting or smelting furnace, a siphon of refractory materialwith metallic casing, open at the suction end for immersion in thefurnace bath, closed at the pouring end with a fusible closure, a riseron the siphon, a vacuum chamber, means for producing avacuum,-fle:-:ible pipe connection from the said vacuum chamber to thesaid riser, valves in the pipe connections, means for moving the siphoninto the pouring position and means for admitting air to the siphon tostop the discharge, substantially as specified.

5. In a melting or smelting furnace, a portable siphon of refractorymaterial in halves 22, 22, a metallic casing in halves 20, 21, means forfastening the halves 20, 21 together, means for making the siphon airtight throughout, the said siphon open at the suction end for immersionin the furnace bath, closed at the pouring end with a fusible closure, ariser on the said siphon and means for exhausting the said siphonthrough the said riser, substantially as specified.

6. In a melting or smelting furnace, a portable siphon of refractorymaterial in halves 22, 22, a solid mouth piece of refractory material23, a metallic casing in halves 20, 21, means for fastening the halves20, 21 together, means for making the siphon air tight throughout, thesaid siphon open at the suction end for immersion in the furnace bath,closed at the pouring end With a fusible closure, a riser on the saidsiphon and means for exhausting the siphon through the said riser,substantially as specified.

r SAMUEL E. HITT.

Witnesses MYRA O. MEANs, J. A. MEANS.

